Diminished synthesis of catalase due to the decrease in catalase mRNA in Japanese-type acatalasemia.

In order to characterize the genetic defect in Japanese-type acatalasemia, we examined catalase synthesis in the cultured fibroblasts isolated from a patient suffering from this disease. The transcript of the mutant catalase gene was also analyzed by Northern blotting. It was demonstrated that the severe reduction in catalase protein in the acatalasemic patient is due to the defective synthesis of the enzyme caused by the lack of catalase mRNA. Using Southern blotting, we did not detect large deletion, insertion or rearrangement in the mutant catalase gene as compared with the normal one. We conclude that Japanese-type acatalasemia in this study is resulted by a small mutation in the non-coding region of catalase gene which affects some step in the catalase mRNA metabolism.